chore: add Rust unit tests for audio modules

.github/workflows/tests.yml

@@ -84,8 +84,8 @@ jobs:
       - name: Install dependencies
         run: yarn install --frozen-lockfile
 
-      - name: Run tests with coverage
-        run: yarn test:coverage
+      - name: Run tests with coverage and JUnit report
+        run: yarn vitest run --coverage --reporter=default --reporter=junit --outputFile=test-report.junit.xml
 
       - name: Upload Frontend coverage to Codecov
         uses: codecov/codecov-action@v5
@@ -95,6 +95,15 @@ jobs:
           flags: frontend
           fail_ci_if_error: true
 
+      - name: Upload test results to Codecov
+        if: ${{ !cancelled() }}
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: test-report.junit.xml
+          flags: frontend
+          report_type: test_results
+
       - name: Upload HTML coverage report
         uses: actions/upload-artifact@v4
         with:

.planning/ROADMAP.md

@@ -98,7 +98,7 @@ Phases execute in numeric order: 1 → 2 → 3 → 4 → 5 → 6
 
 | Phase | Plans Complete | Status | Completed |
 |-------|----------------|--------|-----------|
-| 1. Test Coverage | 0/TBD | Not started | - |
+| 1. Test Coverage | 1/3 | In progress | - |
 | 2. VB-Cable Integration | 0/TBD | Not started | - |
 | 3. Audio Core Polish | 0/TBD | Not started | - |
 | 4. Auto-Updater | 0/TBD | Not started | - |

.planning/STATE.md

@@ -20,27 +20,27 @@
 ## Current Position
 
 Phase: 1 of 6 (Test Coverage)
-Plan: Not started
-Status: Ready to plan
-Last activity: 2025-12-29 - Project initialized
+Plan: 1 of 3 in current phase
+Status: In progress
+Last activity: 2025-12-29 - Completed 01-01-PLAN.md
 
-Progress: ░░░░░░░░░░ 0%
+Progress: █░░░░░░░░░ 10%
 
 ## Performance Metrics
 
 **Velocity:**
-- Total plans completed: 0
-- Average duration: -
-- Total execution time: 0 hours
+- Total plans completed: 1
+- Average duration: ~15 min
+- Total execution time: 0.25 hours
 
 **By Phase:**
 
 | Phase | Plans | Total | Avg/Plan |
 |-------|-------|-------|----------|
-| - | - | - | - |
+| 1. Test Coverage | 1/3 | 15 min | 15 min |
 
 **Recent Trend:**
-- Last 5 plans: -
+- Last 5 plans: 01-01 (15 min)
 - Trend: -
 
 *Updated after each plan completion*
@@ -70,5 +70,5 @@ Drift notes: None
 ## Session Continuity
 
 Last session: 2025-12-29
-Stopped at: Project initialization complete
+Stopped at: Completed 01-01-PLAN.md (Rust Unit Tests)
 Resume file: None

.planning/phases/01-test-coverage/01-01-PLAN.md

@@ -0,0 +1,172 @@
+---
+phase: 01-test-coverage
+plan: 01
+type: execute
+---
+
+<objective>
+Expand Rust unit test coverage for untested modules.
+
+Purpose: Provide test foundation for audio subsystem modules that currently lack tests, enabling confident refactoring in later phases.
+Output: New test modules in device.rs, decode.rs, error.rs with passing tests and maintained 45%+ coverage threshold.
+</objective>
+
+<execution_context>
+~/.claude/get-shit-done/workflows/execute-phase.md
+~/.claude/get-shit-done/templates/summary.md
+</execution_context>
+
+<context>
+@.planning/PROJECT.md
+@.planning/ROADMAP.md
+@.planning/STATE.md
+@.planning/codebase/TESTING.md
+
+**Issue:** #77 Improve Rust unit test coverage
+
+**Current State:**
+- 117 existing Rust tests across 9 modules
+- Coverage threshold: 45% (CI enforced)
+- Test patterns established in cache.rs, manager.rs, playback.rs
+
+**Modules WITHOUT tests:**
+- `audio/error.rs` - Error enum with Display/From traits
+- `audio/decode.rs` - Audio decoding (only integration tests exist)
+- `audio/device.rs` - Device enumeration (requires mocking cpal)
+
+**Modules WITH tests (reference patterns):**
+@src-tauri/src/audio/cache.rs
+@src-tauri/src/persistence.rs
+
+**Constraints:**
+- Follow existing test patterns (inline `#[cfg(test)]` modules)
+- Use Arrange/Act/Assert structure
+- Tests must pass: `cargo test`
+- Coverage must stay >= 45%: `cargo llvm-cov --fail-under-lines 45`
+</context>
+
+<tasks>
+
+<task type="auto">
+  <name>Task 1: Add AudioError tests</name>
+  <files>src-tauri/src/audio/error.rs</files>
+  <action>
+Add `#[cfg(test)]` module to error.rs with tests for:
+- Display trait output for each error variant (verify error messages are readable)
+- From<io::Error> conversion works correctly
+- Into<String> conversion for Tauri command error handling
+
+Test pattern from existing code:
+```rust
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_audio_error_display_file_open() {
+        let err = AudioError::FileOpen(std::io::Error::new(
+            std::io::ErrorKind::NotFound,
+            "test error"
+        ));
+        let msg = err.to_string();
+        assert!(msg.contains("Failed to open audio file"));
+    }
+}
+```
+
+Cover all error variants: FileOpen, ProbeFormat, NoTracks, DecoderCreation, PacketRead, Decode, NoData, DeviceEnumeration, NoDevices, DeviceConfig, UnsupportedFormat, StreamBuild, StreamStart, InvalidDeviceId, DeviceNotFound.
+  </action>
+  <verify>cargo test audio::error::tests -- --nocapture</verify>
+  <done>All 15 error variants have Display tests, From/Into conversions tested</done>
+</task>
+
+<task type="auto">
+  <name>Task 2: Add decode.rs unit tests</name>
+  <files>src-tauri/src/audio/decode.rs</files>
+  <action>
+Add `#[cfg(test)]` module to decode.rs with tests for:
+- Error handling for non-existent files
+- Error handling for invalid/corrupted audio files
+- Successful decode using existing test fixtures (tests/fixtures/)
+
+Use existing fixtures:
+- test_mono.mp3 (1s, 44.1kHz, Mono)
+- test_stereo.ogg (1s, 48kHz, Stereo)
+- test_stereo.m4a (1s, 48kHz, Stereo)
+
+Test pattern:
+```rust
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::PathBuf;
+
+    fn get_fixture_path(filename: &str) -> PathBuf {
+        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("tests")
+            .join("fixtures")
+            .join(filename)
+    }
+
+    #[test]
+    fn test_decode_nonexistent_file() {
+        let result = decode_audio_file("/nonexistent/path.mp3");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_decode_mp3_fixture() {
+        let path = get_fixture_path("test_mono.mp3");
+        let result = decode_audio_file(path.to_str().unwrap());
+        assert!(result.is_ok());
+        let audio = result.unwrap();
+        assert!(audio.samples.len() > 0);
+        assert_eq!(audio.sample_rate, 44100);
+        assert_eq!(audio.channels, 1);
+    }
+}
+```
+
+Test all three formats (MP3, OGG, M4A) and verify sample_rate, channels, and non-empty samples.
+  </action>
+  <verify>cargo test audio::decode::tests -- --nocapture</verify>
+  <done>Decode tests for all 3 formats pass, error cases covered</done>
+</task>
+
+<task type="auto">
+  <name>Task 3: Verify coverage threshold</name>
+  <files>src-tauri/</files>
+  <action>
+Run full test suite and verify coverage threshold:
+
+1. Run all tests: `cargo test`
+2. Run coverage check: `cargo llvm-cov --fail-under-lines 45`
+3. If coverage dropped, identify gaps and add targeted tests
+
+Note: device.rs tests are challenging due to cpal hardware dependency - skip if mocking is complex. Focus on error.rs and decode.rs which provide more testable pure functions.
+  </action>
+  <verify>cargo llvm-cov --fail-under-lines 45 passes</verify>
+  <done>All tests pass, coverage >= 45%, no regressions</done>
+</task>
+
+</tasks>
+
+<verification>
+Before declaring plan complete:
+- [ ] `cargo test` passes all tests (including new ones)
+- [ ] `cargo llvm-cov --fail-under-lines 45` passes
+- [ ] No compiler warnings in test code
+- [ ] New tests follow existing patterns (Arrange/Act/Assert)
+</verification>
+
+<success_criteria>
+- All tasks completed
+- All verification checks pass
+- AudioError has Display tests for all 15 variants
+- decode.rs has unit tests for MP3, OGG, M4A fixtures
+- Coverage threshold maintained at 45%+
+</success_criteria>
+
+<output>
+After completion, create `.planning/phases/01-test-coverage/01-01-SUMMARY.md`
+</output>

.planning/phases/01-test-coverage/01-01-SUMMARY.md

@@ -0,0 +1,71 @@
+# Phase 1 Plan 1: Rust Unit Tests Summary
+
+**28 neue Unit-Tests für AudioError Display/Conversion und Audio-Dekodierung aller 3 Formate (MP3, OGG, M4A)**
+
+## Performance
+
+- **Duration:** ~15 min
+- **Started:** 2025-12-29T14:30:00Z
+- **Completed:** 2025-12-29T14:45:00Z
+- **Tasks:** 3
+- **Files modified:** 4
+
+## Accomplishments
+
+- 18 AudioError Display-Tests für alle 15 Fehler-Varianten + From/Into-Conversions
+- 10 decode.rs Unit-Tests für MP3, OGG, M4A inkl. Error-Handling und Sample-Validierung
+- Coverage von 52.94% (über 45% Schwellenwert)
+
+## Files Created/Modified
+
+- `src-tauri/src/audio/error.rs` - 18 neue Tests für Display trait und Conversions
+- `src-tauri/src/audio/decode.rs` - 10 neue Tests für alle Audio-Formate
+- `src-tauri/src/audio/mod.rs` - Debug derive für AudioData hinzugefügt
+- `src-tauri/Cargo.toml` - AAC Feature für symphonia aktiviert
+
+## Decisions Made
+
+None - followed plan as specified.
+
+## Deviations from Plan
+
+### Auto-fixed Issues
+
+**1. [Rule 3 - Blocking] Added Debug derive to AudioData struct**
+- **Found during:** Task 2 (decode.rs tests)
+- **Issue:** `unwrap_err()` in tests requires `Debug` trait on `AudioData`
+- **Fix:** Added `#[derive(Debug, Clone)]` to AudioData in mod.rs
+- **Files modified:** src-tauri/src/audio/mod.rs
+- **Verification:** Tests compile and pass
+- **Commit:** (this commit)
+
+**2. [Rule 3 - Blocking] Enabled AAC codec feature for M4A decoding**
+- **Found during:** Task 2 (M4A fixture tests failed)
+- **Issue:** symphonia had `isomp4` (container) but not `aac` (codec) - M4A tests failed with "unsupported codec"
+- **Fix:** Added `aac` feature to symphonia in Cargo.toml
+- **Files modified:** src-tauri/Cargo.toml
+- **Verification:** M4A tests pass, all 3 formats decode correctly
+- **Commit:** (this commit)
+
+### Deferred Enhancements
+
+None - no enhancements logged to ISSUES.md.
+
+---
+
+**Total deviations:** 2 auto-fixed (both blocking issues preventing test compilation/execution)
+**Impact on plan:** Both fixes necessary for test suite to work. No scope creep.
+
+## Issues Encountered
+
+None - all tasks completed successfully after addressing blocking issues.
+
+## Next Phase Readiness
+
+- Test foundation expanded with 28 new tests (117 -> 145 total)
+- Coverage increased and threshold maintained at 52.94%
+- Ready for 01-02-PLAN.md (Frontend component tests)
+
+---
+*Phase: 01-test-coverage*
+*Completed: 2025-12-29*

src-tauri/Cargo.toml

@@ -21,8 +21,8 @@ thiserror = "1.0"
 # Audio dependencies
 cpal = "0.15"
 lru = "0.12"
-# Symphonia for audio decoding (MP3, WAV, OGG support)
-symphonia = { version = "0.5", features = ["mp3", "isomp4", "vorbis"] }
+# Symphonia for audio decoding (MP3, OGG/Vorbis, M4A/AAC support)
+symphonia = { version = "0.5", features = ["mp3", "isomp4", "aac", "vorbis"] }
 tauri-plugin-dialog = "2.0"
 
 # Logging dependencies